docs: def build_swagger_data(self, loader):
          """ Prepare data when schema loaded
  
          :param swagger_schema: loaded schema
          """
          if self.is_built:
              return
          self.is_built = True
          self._required = []
          self._parameters = {}
          if not self._swagger_data:
              return
          elif loader is not None:
              data = loader.resolve_data(self._swagger_data).copy()
          else:
              data = self._swagger_data
  
          for param in data.get('parameters', ()):
              p = param.copy()
              if loader is None:
                  p = allOf(p)
              name = p.pop('name')
              self._parameters[name] = p
              if p.pop('required', False):
                  self._required.append(name)